Stability of lipases in miniemulsion systems: Correlation between secondary structure and activityPublication date: Available online 12 March 2018 Source:Enzyme and Microbial Technology Author(s): Ana C.D. Pfluck, Dragana P.C. de Barros, Luís P. Fonseca, Eduardo P. Melo The exploitation of an efficient enzymatic system to perform biopolymers synthesis, namely polyesters from dicarboxylic acids and dialcohols, requires the evaluation of the enzyme operational stability. This becomes particularly relevant when non-conventional media, such as miniemulsions, are used due to the inhomogeneity of the reaction media and presence of surfactants and high concentrations of organic compounds which might be deleterious to ...Source: Enzyme and Microbial Technology - March 13, 2018 Category: Biotechnology Source Type: research

Engineering the residues on “A” surface and C-terminal region to improve thermostability of nitrilasePublication date: Available online 5 March 2018 Source:Enzyme and Microbial Technology Author(s): Zhe Xu, Ting Cai, Neng Xiong, Shu-Ping Zou, Ya-Ping Xue, Yu-Guo Zheng Nitrilases can hydrolyze nitriles to corresponding carboxylic acids in one single step, which have great potential as valuable biocatalysts for chemical synthesis. However, the poor thermostability of the nitrilases restrict their applications in industry. In this work, error-prone PCR and site-directed mutagenesis were utilized to improve the thermostability of nitrilases. Several mutants (AcN-Q339K, AcN-Q343K, AcN-T201F, AcN-T201W, AcN-T201L, AcN-T201I) w...Source: Enzyme and Microbial Technology - March 6, 2018 Category: Biotechnology Source Type: research

Optical method for detecting oxygen via the chromogenic reaction catalyzed by polyphenol oxidasePublication date: Available online 1 March 2018 Source:Enzyme and Microbial Technology Author(s): Abdelaziz Bouchaib, Abdellatif Ben abdellah, Mohamed Bakkali, Amine Laglaoui, Abdelhay Arakrak, Carlo Carboni, Abdelaziz Benjouad, Amal Maurady The present work describes a method for detecting the ingress of gas phase oxygen into packed food. It uses the enzyme polyphenol oxidase (PPO)from Mushroom and Mediterranean dwarf palm. The PPO is incorporated into an indubiose film along with a non-toxic polyphenol such as gallic acid or chlorogenic acid. If exposed to oxygen, the test spot undergoes an irreversible and visible colo...Source: Enzyme and Microbial Technology - March 2, 2018 Category: Biotechnology Source Type: research

Enantioselective sulfoxidations employing the thermostable cyclohexanone monooxygenase from Thermocrispum municipalePublication date: Available online 21 February 2018 Source:Enzyme and Microbial Technology Author(s): Gonzalo de Gonzalo, Antonio Franconetti The recently discovered cyclohexanone monooxygenase from Thermocrispum municipale (TmCHMO) was employed in the preparation of different optically active sulfoxides. This novel Baeyer-Villiger monooxygenase (BVMO) shows a similar substrate specificity and selectivity when compared with the prototype CHMO from Acinetobacter calcoaceticus. Interestingly, TmCHMO is able to catalyse the asymmetric sulfoxidations at relatively high temperatures, substrate concentrations and in the presenc...Source: Enzyme and Microbial Technology - February 22, 2018 Category: Biotechnology Source Type: research

Producing functional recombinant human keratinocyte growth factor in Pichia pastoris and investigating its protective role against irradiationPublication date: Available online 5 January 2018 Source:Enzyme and Microbial Technology Author(s): Zahra Bahadori, Hamid Reza Kalhor, Seyed Javad Mowla Keratinocyte Growth Factor (KGF) is a paracrine-acting, epithelial mitogen that plays a prominent role in the regeneration of damaged epithelial tissues. In spite of different attempts to produce recombinant human KGF in many organisms, including bacteria, mammalian cells, plant cells and insect cells; production of recombinant form suffers from lower yields and recovery relative to other recombinant proteins of similar size and properties. Due to many advantages of Pichi...Source: Enzyme and Microbial Technology - January 6, 2018 Category: Biotechnology Source Type: research

Stereoselective hydroxylation of isophorone by variants of the cytochromes P450 CYP102A1 and CYP101A1Publication date: Available online 5 January 2018 Source:Enzyme and Microbial Technology Author(s): Shaghayegh Dezvarei, Joel H.Z. Lee, Stephen G. Bell The stereoselective oxidation of hydrocarbons is an area of research where enzyme biocatalysis can make a substantial impact. The cyclic ketone isophorone was stereoselectively hydroxylated (≥95%) by wild-type CYP102A1 to form (R)-4-hydroxyisophorone, an important chiral synthon and flavour and fragrance compound. CYP102A1 variants were also selective for 4-hydroxyisophorone formation and the product formation rate increased over the wild-type enzyme by up to 285-fold, ...Source: Enzyme and Microbial Technology - January 6, 2018 Category: Biotechnology Source Type: research

Identification of (R)-selective ω-aminotransferases by exploring evolutionary sequence spacePublication date: Available online 23 December 2017 Source:Enzyme and Microbial Technology Author(s): Eun-Mi Kim, Joon Ho Park, Byung-Gee Kim, Joo-Hyun Seo Several (R)-selective ω-aminotransferases (R-ωATs) have been reported. The existence of additional R-ωATs having different sequence characteristics from previous ones is highly expected. In addition, it is generally accepted that R-ωATs are variants of aminotransferase group III. Based on these backgrounds, sequences in RefSeq database were scored using family profiles of branched-chain amino acid aminotransferase (BCAT) and D-alanine aminotrans...Source: Enzyme and Microbial Technology - December 24, 2017 Category: Biotechnology Source Type: research

An enzymatic alternative for the synthesis of nucleoside 5 ′-monophosphatesPublication date: Available online 19 December 2017 Source:Enzyme and Microbial Technology Author(s): Esteban D. Gudiño, Julia Y. Santillán, Luis E. Iglesias, Adolfo M. Iribarren A new procedure was carried out for the synthesis of nucleoside 5′-monophosphates, involving the use of two enzymes. The first step applied phospholipase D from Streptomyces netropsis and phosphatidylcholine as phosphatidyl donor, to give 5′-(3-sn-phosphatidyl) nucleosides (C, U, A, I). These were selectively hydrolysed in the second step by the action of phospholipase C from Bacillus cereus to produce the respective 5&p...Source: Enzyme and Microbial Technology - December 20, 2017 Category: Biotechnology Source Type: research

Enantioselective synthesis of (R)-phenylephrine by Serratia marcescens BCRC10948 cells that homologously express SM_SDRPublication date: Available online 10 December 2017 Source:Enzyme and Microbial Technology Author(s): Yi-Chia Kuan, Yue-Bin Xu, Wen-Ching Wang, Ming-Te Yang A short-chain dehydrogenase/reductase from Serratia marcescens BCRC10948, SM_SDR, has been cloned and expressed in Escherichia coli for the bioconversion of 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) to (R)-phenylephrine[(R)-PE]. However, only 5.11mM (R)-PE was obtained from 10mM HPMAE after a 9h conversion in the previous report. To improve the biocatalytic efficiency, the homologous expression of the SM_SDR in S. marcescens BCRC10948 was achieved using the...Source: Enzyme and Microbial Technology - December 10, 2017 Category: Biotechnology Source Type: research

A Process for Production of Trehalose by Recombinant Trehalose Synthase and Its PurificationIn this study, a TreS from Pseudomonas putida ATCC47054 was expressed in E. coli BL21(DE3) via plasmids pET15b and pET22b. pET15b-treS showed better plasmid stability and TreS expression, which revealed that the highest activity, 39866±1420U/(g dry cell weight) at the final lactose concentration of 4g/L for 7h at 27°C in a 5-L fermentor at pH 8.0. The use of 30% (w/v) high-maltose syrup as a substrate can extend the temperature tolerance of TreS to 60°C. More than 64% of maltose can be converted into trehalose by adding 200U of TreS per gram of maltose at 50°C for 24h. The total sugar content of the treh...Source: Enzyme and Microbial Technology - December 2, 2017 Category: Biotechnology Source Type: research

Utilization of distillery wastewater for hydrogen production in one-stage and two-stage processes involving photofermentationIn this study, distillery wastewater was treated by dark fermentation or photofermentation alone, and by sequential dark and photofermentation processes using anaerobic saccharolytic consortium and purple nonsulfur bacteria. Combination of dark and photofermentation resulted in the maximal H2 yield of 17.6L/L of distillery waste with chemical oxygen demand 40g/L. It is equivalent to 205kJ/L distillery wastewater and corresponds to recovery of approximately 4-8% of energy consumed during ethanol production. Optimal performance of photofermentation was observed at 20% concentration of pre-fermented distillery waste. In photo...Source: Enzyme and Microbial Technology - November 29, 2017 Category: Biotechnology Source Type: research

Improved peroxide biosensor based on Horseradish Peroxidase/Carbon Nanotube on a thiol-modified gold electrodePublication date: Available online 16 November 2017 Source:Enzyme and Microbial Technology Author(s): A.K.M. Kafi, M. Naqshabandi, Mashitah M. Yusoff, Maxwell J. Crossley A new 3-dimensional (3D) network of crosslinked Horseradish Peroxidase/Carbon Nanotube (HRP/CNT) on a thiol-modified Au surface has been described in order to build up the effective electrical wiring of the enzyme units with the electrode. The synthesized 3D HRP/CNT network has been characterized with cyclic voltammetry and amperometry which results the establishment of direct electron transfer between the redox active unit of HRP and the Au surface. Ele...Source: Enzyme and Microbial Technology - November 17, 2017 Category: Biotechnology Source Type: research

Biochemical characterization of a novel tyrosine phenol-lyase from Fusobacterium nucleatum for highly efficient biosynthesis of l-DOPAIn this study, a novel TPL from Fusobacterium nucleatum (Fn-TPL) was successfully overexpressed in Escherichia coli and screened for l-DOPA synthesis with a specific activity of 2.69Umg−1. Fn-TPL was found to be a tetramer, and the optimal temperature and pH for α, β-elimination of l-tyrosine was 60°C and pH 8.5, respectively. The enzyme showed broad substrate specificity toward natural and synthetic l-amino acids. Kinetic analysis suggested that the k cat/K m value for l-tyrosine decomposition was much higher than that for l-DOPA decomposition, while Fn-TPL exhibited similar catalytic efficiency for s...Source: Enzyme and Microbial Technology - November 15, 2017 Category: Biotechnology Source Type: research

Identification and characterization of the first β-1,3-d-xylosidase from a gram-positive bacterium, Streptomyces sp. SWU10Publication date: Available online 10 November 2017 Source:Enzyme and Microbial Technology Author(s): Pornpimol Phuengmaung, Daisuke Fujiwara, Wasana Sukhumsirichart, Tatsuji Sakamoto In previous reports, we characterized four endo-xylanases produced by Streptomyces sp. strain SWU10 that degrade xylans to several xylooligosaccharides. To obtain a set of enzymes to achieve complete xylan degradation, a β-d-xylosidase gene was cloned and expressed in Escherichia coli, and the recombinant protein, named rSWU43A, was characterized. SWU43A is composed of 522 amino acids and does not contain a signal peptide, indicating th...Source: Enzyme and Microbial Technology - November 10, 2017 Category: Biotechnology Source Type: research

Rational selection of biphasic reaction systems for geranyl glucoside production by Escherichia coli whole-cell biocatalystsPublication date: Available online 8 November 2017 Source:Enzyme and Microbial Technology Author(s): Xenia Priebe, Maximilian Daschner, Wilfried Schwab, Dirk Weuster-Botz Geranyl glucoside, the glucosylated, high-value derivative of the monoterpenoid geraniol, has various applications in the flavor and fragrance industry and can be produced through whole-cell biotransformation of geraniol with Escherichia coli whole-cell biocatalysts expressing the glucosyltransferase VvGT14a. However, the low water solubility and high cytotoxicity of geraniol require the design of a proper biphasic system where the second, non-aqueous ph...Source: Enzyme and Microbial Technology - November 9, 2017 Category: Biotechnology Source Type: research

Rational evolution of the unusual Y-type oxyanion hole of Rhodococcus sp. CR53 lipase LipRPublication date: January 2018 Source:Enzyme and Microbial Technology, Volume 108 Author(s): Belén Infanzón, Pablo H. Sotelo, Josefina Martínez, Pilar Diaz Rhodococcus sp CR-53 lipase LipR was the first characterized member of bacterial lipase family X. Interestingly, LipR displays some similarity with α/β-hydrolases of the C. antartica lipase A (CAL-A)-like superfamily (abH38), bearing a Y-type oxyanion hole, never found before among bacterial lipases. In order to explore this unusual Y-type oxyanion hole, and to improve LipR performance, two modification strategies based on site directed ...Source: Enzyme and Microbial Technology - November 6, 2017 Category: Biotechnology Source Type: research

FCS and ECH dependent production of phenolic aldehyde and melanin pigment from L-tyrosine in Escherichia coliIn this study, we engineered E. coli cells to express L-tyrosine converting enzymes, including tyrosine ammonia-lyase (TAL), p-coumarate 3-hydroxylase (C3H), feruloyl-CoA synthetase (FCS), and enoyl-CoA hydratase/aldolase (ECH). A catabolic circuit, which consisted of the protocatechualdehyde and p-hydroxybenzaldehyde production pathways, was reconstituted through combinatorial production of discrete enzymes. First, cells expressing FCS and ECH could convert each 5mM of caffeic acid and ferulic acid into protocatechualdehyde (70.5%) and vanillin (96.5%), respectively. Second, TAL and C3H were co-expressed with FCS and ECH....Source: Enzyme and Microbial Technology - October 28, 2017 Category: Biotechnology Source Type: research

Cloning and characterization of a novel phenylalanine ammonia-lyase gene from Inonotus baumiiPublication date: Available online 26 October 2017 Source:Enzyme and Microbial Technology Author(s): Weiping Lin, Ao Liu, Caihong Weng, Hui Li, Shiwei Sun, Aihuan Song, Hu Zhu Phenylalanine ammonia-lyase (PAL) gene plays an important role in the synthesis of flavones, lignin, and other bioactive compounds in living organisms. Inonotus baumii, the only known flavone-producing filamentous fungus, is of great importance in the investigation of flavone metabolic pathways. To study the function of PAL enzyme in I. baumii flavone synthesis, a full-length cDNA of pal gene was cloned from I. baumii using DOP-PCR and RACE-PCR. The...Source: Enzyme and Microbial Technology - October 27, 2017 Category: Biotechnology Source Type: research

Maximize rhamnolipid production with low foaming and high yieldIn this study, we assessed the boundaries set by these constraints after optimization of basic parameters such as dissolved oxygen concentration (DO), pH and carbon sources. DO 10% and pH 5.5-5.7 were found optimal; cell growth and/or rhamnolipid production were slower at lower DO (5%) or pH (5.0) while foaming became hard to control at higher DO (30%) or pH (6.0 and 6.5). Although the Pseudomonas aeruginosa strain used was selected for its high rhamnolipid production from glycerol as substrate, soybean oil was still found to be a better substrate that increased specific rhamnolipid productivity to 25.8mg/g cells-h from th...Source: Enzyme and Microbial Technology - October 17, 2017 Category: Biotechnology Source Type: research